You have problems with the physical connections. It would need some technician to check it.

About the double channels that Garyb mentioned: it is simply because the S/Mux mode "sums" both ADAT A and ADAT B to let you have 96kHz sample rate. That means that you will only have 8 channels from the A16.

I put my hands and head in the a16, dismantled completely, by blocking the connectors I finally managed to lock the cables...
On the Pulsar side it's more technical, on 1 mm of connection it causes noise so I have to block the cables so that they can't move anymore, otherwise I have the right to crack but nothing to do with the white noise before.